Field of the Invention
The invention generally relates to the technical field of vehicle steering systems and in particular to the field of steering shafts. More specifically, the invention relates to a steering shaft component, a steering shaft and a production method therefor. In the present document, all components that serve for steering power transmission between a steering wheel and a steering gear are understood to be a “steering shaft”. For example, the term “steering shaft” includes, among other things, those components that are often referred to as “steering column” or “steering spindle”.
Description of Related Art
Hydraulic or electric power-assisted steering systems (“servo steering systems”) are generally used in vehicle construction today. In such steering systems, the steering forces and/or steering movements of the vehicle operator are sensed and converted into actuating motions of a hydraulic valve or into electrical signals.
DE 10 2007 047 827 A1 shows a torque sensor unit with a torsion member configured as a torsion bar. Such designs are well-known in many different forms. Generally, however, steering assemblies with torsion bars require a lot of effort with regard to production and assembly. The torsion bar is a separate component that must be drilled into the steering spindle. In practice, this results in a relatively high percentage of rejects, with an entire assembly having to be rejected in each case if it does not have the desired characteristic curve.
DE 101 20 580 A1 shows a sensor for measuring a torque of a rotating shaft, e.g. a drive or cardan shaft of a motor vehicle. This sensor measures the torsion of the shaft and converts it into an electrical signal. Though the published patent application mentions a possible use of the sensor on a steering shaft of a motor vehicle, this, however, hardly appears feasible because a steering shaft of usual dimensions twists only slightly at the usual steering forces. Thus, a sufficiently exact measurement should be difficult or at least require a lot of effort.